Caroline Duwaerts, PhD, a UC San Francisco researcher, and colleagues fed mice four high-energy diets of identical caloric and nutritional composition for three weeks to six months.
The diets contained 42 percent carbohydrates and 42 percent fats. Researchers monitored weight and glucose tolerance while collecting blood and tissue samples for histology, gene expression and immunophenotyping.
Here’s what they found:
1. All the mice gained weight, but their metabolic outcomes differed.
2. Mice with a starch-oleate diet were more likely to develop hepatic steatosis than those on other diets.
3. Researchers showed how stable isotope incorporation in exaggerated adipose tissue lipolysis developed excess hepatic steatosis.
4. In the mice, adipose tissue lipolysis was related to adipocyte necrosis and inflammation.
5. Researchers reproduced the abnormalities when feeding the mice a mixed-nutrient Western diet of carbohydrates and fats.
Researchers concluded, “The macronutrient composition of the diet exerts a significant influence on metabolic outcome, independent of calories and nutrient proportions. Starch-oleate appears to cause hepatic steatosis by inducing progressive adipose tissue injury.”
The researchers believe the phenocopying effects of starch-oleate could provide insight into how specific nutrients cause metabolically unhealthy obesity.
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